Source : Webster's Revised Unabridged Dictionary (1913)

Archenteron \Arch`en"ter*on\, n. [Pref. arch- + Gr. ?
   intestine.] (Biol.)
   The primitive enteron or undifferentiated digestive sac of a
   gastrula or other embryo. See Illust. under {Invagination}.

Source : WordNet®

archenteron
     n : central cavity of the gastrula; becomes the intestinal or
         digestive cavity